Satellite telephone systems are emerging as a new and important global business. These systems utilize many individual circuits routed through one satellite or a constellation of many satellites to provide communications for terrestrial terminals. One significant advantage of the satellite telephone system is that it provides ubiquitous coverage of large areas of the earth without requiring the construction of many small terrestrial cells.
A problem that can arise in such systems is due to the typically line-of-sight nature of the RF communication links between user terminals and the satellite or satellites providing service to the user terminal. This problem is especially made manifest when the user terminal is carried inside of a building or other structure that effectively blocks the line-of-sight to the satellite.
Studies have shown that RF signals deteriorate inside of buildings at at least twice the rate that they do in free space. That is, instead of -20 dB for a 10 times increase in distance, the signals decrease in amplitude by as much as -40 dB for the same increase in distance. This implies that the signal arriving from a communication satellite is very quickly attenuated to a useless level inside of a building, especially if the free-space link margins may be only about 10 dB to begin with.
It is known in the terrestrial cellular industry to provide repeaters with outdoor terrestrial cellular antennas and amplifiers, and to position antennas indoors. These systems do not, however, discriminate between cellular systems. Furthermore, the tracking of the cell site is not necessary since it is fixed in position, unlike a non-geosynchronous orbit (non-GSO) satellite, such as a low earth orbit (LEO) or a medium earth orbit (MEO) satellite that continuously changes its position with respect to a point on the ground.